Rail cars and tanker trucks, among other transportation vehicles, have been utilized to carry and store myriad items and materials to facilitate unlimited types of commercial activities. From building materials, to gasoline, to chemicals, without such shipping alternatives, the ability for manufacturers to function within different economies would be drastically effected. As it is, there have been few, if any, other transportation methods developed and made available to replace these standard vehicles. The continued utilization of such transportation modes remains unabated and will even grow as population numbers increase.
Such vehicles, though important for commercial enterprise, remain highly susceptible to a number of concerns related primarily to the potential compromise in structural integrity thereof during actual utilization. For instance, volatile chemicals and fuels, as well as highly toxic chemicals are typically transported by rail and tanker truck to myriad destinations. Any compromise of the structure of such a car or tank could lead to highly undesirable spills and even explosions due to any number of actions. If a train is derailed, the chances for spills, emanations, or omissions of fluids and/or gases are currently not only highly likely, but imminently lead to disastrous results. The same holds true for tanker trucks; collisions, jack-knifing, or, other types of accident lead to environmental and other hazardous events that have been known to deleteriously effect individuals involved in such a situation as well as those proximally located to the site itself. Even more horrifying is the chance that a bad actor seeks to discharge a ballistic device on a rail car or tanker truck during transport of hazardous materials. If the materials involved are flammable, the creation of a spark through the contact of the ballistic shell with the metal structure could cause nearly instant immolation of the rail car or tanker (as well as the loss of life in such a vicinity). Even if such an explosion does not occur (or if the materials transported are not flammable, but highly toxic, as an example), the chances for fluid or gaseous materials to escape the rail car or tanker enclosure to the environment in such an instance are significant. Either way, the potential for problems in this manner are very high.
To meet these issues, many different developments have been considered in the past. Certainly, the ability to thicken rail car and tanker walls has been undertaken to strengthen the structures to reduce the propensity for wall failure during an accident or other problematic event. Unfortunately, to do so requires not only the expenditures of greater funds to purchase larger amounts of steel (or other like metal materials) as well as the increased manufacturing costs to produce such resultant bolstered metal objects. As well, the increased weight accorded the finished cars and tankers adds to the fuel consumption necessary to actually transport such devices the requisite distances. In other words, although greater strength could be provided through extra steel (or other like metal) layers, even in terms of intricate layering techniques, the base costs and the overall weight added militate against such an alternative. Even with these strengthened wall units in place, the capability of a ballistic device to create a spark upon breach thereof would cause a spark that would, in turn, cause any flammable materials to explode therein. There thus remains a significant need to avoid such costly and, ultimately, ineffective means for all possible difficulties (ballistic shooting, derailing, crashing, and the like) such transport modes could face.
Other developments have thus been proposed to avoid such challenges. For example, the utilization of polyurea as a layering coating over and between steel layers has provided greater strength as well as some degree of spark dissipation in certain situations. Polyurea has shown to be relatively effective to combat structural integrity failures in other end-uses and thus its use as a layering component has shown some promise within metal wall composites. The major deficiency, however, involved with this layering objective is that the retention of polyurea on such steel (or other like metal) surface is highly suspect; delamination is a typical result, in other words, as the polyurea resin does not easily remain adhered to such metal surfaces during a ballistic event. Even with an epoxy binding agent, the failure point exists at the epoxy-metal or epoxy-polyurea interfaces, leaving the finished wall susceptible to failure upon a bullet strike since any compromised interface will prevent the operation of polyurea to re-seal at the point of rupture. Additionally, the need for polyurea between layers requires extra metal materials that, again, add to the overall weight and costs of manufacture. Thus, the lack of full reliability for rupture sealing at each point within the wall structure coupled with the extra costs/weight, as above, militate against this seemingly simple remedy.
Unfortunately, the standard procedures to reduce the need for other metal layers and/or the potential for delamination of polyurea from composite layers has proven ineffective as well. For example, the theory that stronger fabrics, such as two-dimensional and three-dimensional weaves, that exhibit individual levels of tensile strengths on par, at least, with basic thin-wall metal structures, and sometimes dependent on the fiber types utilized, has been proposed for such rail cars and tankers. The basic problem, though, remains that such fabrics must not only exhibit the necessary rupture prevention (or at least reduction) capability, but also the ability to remain properly laminated to the polyurea materials during and after a destructive event. Such standard weaves, though, have not proven reliable enough to the necessary degree. Even with polyaramid and other like ballistics fibers, the weakest link within the overall composite structure, such as the resin layers between woven fabrics, have proven to be ineffective with certain high-force destructive events. Polyurea can be coated on such fabric surfaces, but the individual layers between fabric portions create a resin-rich environment that is highly susceptible to delamination upon ballistics penetrations. In such situations, the polyurea component will not be able to re-contact effectively thereafter to re-seal a resultant opening within the base structure. Furthermore, the need to layer multiple weaves on one another to accord the necessary thickness and strength to the finished wall structure leaves the composite involved highly susceptible to detachment (or, again, delamination) of individual layers such that rupture failure is imminent. Unless the multi-layered structured remains intact, the ability of the structure to impart the necessary rupture prevention (or reduction) is compromised, in other words. Additionally, such weaves are typically of standard configurations (basket weaves, for instance) that fail to provide the strongest tensile strength results to the overall product. Even with polyurea applied thereto, then, the potential for composite fabric failure prevents the polyurea, even if its lamination thereto is not compromised, from properly operating during a ballistic or other destructive event.
Thus, the next step undertaken was to investigate the potential for quasi three-dimensional fabric weaves as structural composites. Such quasi 3D fabrics are far less susceptible to damage and delamination of layers due to the presence of connecting fibers between layers to effectuate greater levels of strength between individual structures. In other words, with 3D fabrics, there are multiple layers that are fused together in some manner, but still highly susceptible to delamination during a shearing event (such as, again, a crash, ballistics penetration, or other like destructive scenario). Quasi 3D structures include multiple layers but are actually configured such that a middle layer includes fibers that are integrated within both the upper and lower layer. This outlay then creates far greater strength for the overall fabric as the chances of layer separation are drastically reduced. Combination with polyurea may then allow for a certain improved level of reliability over the past developments. Unfortunately, however, the actual weave configurations integrated within these quasi 3D structures have been lacking the overall strength needed to comport the highest level of protection from a rupture action. Simply put, even with a structure that does not easily come apart in layers during such an event, the base weave configuration itself leaves the potential for overall rupture of the fabric itself, rather than just delamination or separation of layers. Again, even with polyurea properly applied thereto, and thus the potential, at least, for a resealing action to commence immediately upon rupture or ballistics penetration, if the fabrics themselves rupture to great a degree, then the overall platform is weakened and may allow for gas, fluid, etc., escape thereafter.
Thus, there remains a significant need to provide as failsafe a structure to adhere to a base metal wall in order to accord a resealing method thereto that acts instantaneously upon compromise of any portion of such a strengthened wall. Again, without a fabric that provides not only high-strength protection to absorb destructive forces upon a quick, possibly deliberative and penetrative collision or ballistic event to a subject metal wall structure, and without a properly applied resealing polyurea material that will not only aid to absorb destructive forces but will also reseal and cover the resultant opening within the subject wall during such an event, there is simply lacking the necessary level of reliability and effectiveness for proper protection in this situation. To date, again, there is nothing provided the pertinent industries to such a needed level.